Insecticidal compositions



Patented Aug. 14, 1951 INSECTICIDAL COMPOSITIONS Joseph Henry Percy,Woodmere, N. Y., and Her- South Orange, N. J., as-

bert

Frank Neumann signors to Colgate- Palmolive-Peet Company,

Jersey City, N. J., a corporation of Delaware No Drawing. ApplicationMay 4, 1946, Serial No. 667,486

6 Claims. 1

The present invention relates to insecticidal compositions which areparticularly adapted for the protection of fruit trees and other foodcrops.

Organic insecticides such as dichlorodiphenyltrlchloroethane(DDT), beingeffective in very small amounts, are usually applied to the thing to beprotected against the ravages of insects as a dust or spray comprising afew per cent of insecticide in an inert carrier It has been proposed tomake a coarse powder or dust by dissolving the insecticide in a waxysolid such as stearic acid, glycerylmonostearate, cetyl alcohol, or thelike, and pulverizing the solid solution. While the waxy solid has beensaid to protect the insecticide against rain, the coarse powder cannotbe used satisfactorily on plants. Sprays comprising the insecticide insolution or suspension in liquids such as alcohol, petroleum cuts,water, etc., have also been proposed and used some extent on plants withand without binders. If no binder were present, the insecticide wasquite rapidly washed off the plants which were exposed to the weather.If a binder were used which effectively prevented rain from washing offthe insecticide, difficulty was experienced in removing the binder andinsecticide from the harvested fruit or other food crop.

We have now discovered that a solution of an organic insecticide in afatty acid monoester of a polyhydric compound, e. g., propylene glycolmonoesters of coconut oil fatty acids, provides an insecticidalcomposition which can be readily dispersed in water, particularly in thepresence of a small amount of emulsifying agent, to form a dilute spraycomposition admirably adapted for spraying fruit trees and other foodcrops since it adheres well to the surface of the plants, is not washedoff to any substantial extent by rainwater, and yet is easily washed offthe harvested fruit or other crop by aqueous solutions of emulsifyingagents.

The present invention is applicable to all organic insecticidesincluding rotenone, nicotine, pyrethrum, derris, beta-naphthol,thiocyanates, p dichlorobenzene, dichlorodiphenyltrichloroethane (DDT),etc.

In the preferred form of the invention the monoester used as the carrierfor the insecticide is liquid at the temperatures to which thecomposition will be exposed in use. Propylene glycol monoesters ofcoconut oil fatty acids made by reacting coconut oil fatty acids with anexcess of propylene glycol at elevated temperature, for

example, have'very satisfactory properties forthis use. It can dissolveup to about 17% by weight of dichlorodiphenyltrichloroethane DDT) at 24C.; it melts at about 3 C.; it is practically insoluble in water; itforms a dispersion in water very readily, particularly in the presenceof an emulsifying agent; it spreads easily on and adheres tightly tofruit, leaves and other plant surfaces; and it can be removed easily bywashing with an aqueous solution of an emulsifying agent. Other liquidmonoesters of fatty acids and polyhydric alcohols have similarproperties and advantages, including propylene glycol monolaurate,ethylene glycol monocaprate, glyceryl monocaproate, mixtures of glycoland glyceryl monoesters of palm kernel oil fatty acids such as areobtained by reacting palm kernel oil with an excess of glycol atelevated temperature in the presence of liquid water and/or an alkalinecatalyst, etc.

A convenient way of preparing an insecticidal composition for market inaccordance with the present invention is to dissolve the insecticide inthe monoester and to incorporate therein a small percentage, preferablyabout 0.5% to 2.0%, of an emulsifying agent. The insecticide andemulsifying agent, within the amounts specified herein, dissolve in themonoester to give a clear solution. The use of an amount of insecticidegreater than will go into solution in the monoester is wasteful. If moreemulsifying agent is used than will dissolve in the monoester, theadhesion of the composition to plant surfaces during rain storms isdecreased. The solution comprising the insecticide and emulsifying agentcan either be put directly into bottles, cans, or the like for sale orit can be dispersed in water to form a concentrated oil in wateremulsion which can be similarly packaged. The consumer prepares thespray liquid by pouring a small quantity of the mixture into water andstirring. The monoester with the insecticide in solution readilydisperses throughout the water in minute globules, giving an emulsion ofthe product in water which is relatively stable and readily sprayed.

Monoesters which are solid at the temperatures encountered in the use ofthe material can also be employed. Among these are glyceryl monoestersof coconut oil, palm kernel oil, palm oil, etc., ethylene glycolmonostearate, diethylene glycol monostearate, propylene glycolmonostearate, ,etc. Insecticidal compositions of such materials can beprepared by melting the monoester, dissolving the organic insectidetherein and emulsifying the mixture in water at a temperature above themelting point of the ester with the aid of an emulsifying agent to forma concentrated product. As soon as the ester and insecticide have beenthoroughly dispersed in the water the temperature may be allowed tofall. As it passes through the melting point of the monoester, thedroplets of the dispersed phase will solidify as discrete particles thatremain suspended in the liquid. This suspension can be put in bottles,cans, etc., and used in the same way as the liquid type. The solidparticles themselves do not cling as tenaciously to the surfaces offruits, leaves, etc., as droplets of liquid monoesters but theemulsifying agent, in the proportions used, serves as quite an effectivebinder, even during rain storms.

The fatty acid monoesters of polyhydric organic compounds contemplatedby the present invention include the polyhydric alcohol esters of fattyacids having from about six to about twentyfour carbon atoms permolecule. Among the polyhydric alcohols which can be used are the diols,such as ethylene glycol, propylene glycol, trimethylene glycol, butanediols, etc.; glycerol, butane trihydroxy alcohols, etc.; erythritol,mannitol, sorbitol, etc. This class of polyhydroxy compounds may bedefined as aliphatic polyhydric alcohols having from two to six carbonatoms per molecule. Preferred alcohols are the diand trihydroxy alcoholshaving from two to four carbon atoms per molecule including propyleneglycol, ethylene glycol, diethylene glycol, and glycerol.

The fatty acids which are esterified with the polyhydroxy organiccompounds are preferably the fatty acids obtained from naturallyoccurring fats, oils, waxes, etc., including coconut oil, palm kerneloil. palm oil, tallow, fish oils, spermaceti, carnauba wax, etc.Synthetic fatty acids, such as those obtained by the oxidation ofpetroleum oils, however, may also be used.

The monoesters obtainable commercially are not pure compounds butcontain minor amounts of higher esters, free fatty acids, free alcohol,etc. A commercially available liquid monoester product which is verysatisfactory for the present invention comprises approximately:

Percent Propylene glycol monoesters of coconut fatty acids l7 Propyleneglycol diesters 1'! Free fatty acids 2% Propylene glycol 2 Water 1 Themonoesters of fatty acids with polyhydric alcohols are capable ofdissolving organic insecticides in very substantial proportions asillustrated by the solubility of DDT in propylene glycol monococate. Thepercentage of organic insecticide dissolved in the monoester for use inthe present invention may vary from a fraction of one per cent up to themaximum amount that can be taken into solution, depending upon theconcentration of the insecticide it is desired to have present on thesurfaces of the plants being treated. Ordinarily about 5 to 15% ofinsecticide is a satisfactory proportion. The amount of thisinsecticidal composition which is dispersed in a given quantity of waterin preparing the spray mixture can also be varied widely, thus giving anadditional control over the concentration of the active ingredient thatis applied to the plant surfaces The emulsifying agent is advantageouslyused in preparing a spray composition to give easier dispersion of themonoester in the water. While itcanbeaddedatthetimeofpreparationof thespray mixture, it is preferred to add it to the monoester as alreadydescribed. The insecticidal composition should be so compounded thatwhen the proper amount is added to water to form a spray mixture, theemulsifying agent will be present within the range of 0.001 to 0.1%based on the water. Even higher percentages of emulsifying agent may beused if desired, but amounts larger than about 0.1% present noadditional advantages and may lessen the adhesion of the insecticidalcomposition on the plant surfaces during rain storms. Within thepreferred range of emulsifying agent, the spray, once it has dried, isnot easily removed by rain. The emulsifying agents that may be used forthis purpose are water-soluble cationic, anionic and nonionic materialswhich have dispersing and/or emulsifying properties, including amines,soap, synthetic detergents such as the organic sulphates andsulphonates, polyether alcohol condensates, etc.

The following examples are given for the purpose of illustrating theinvention:

Example I A suitable liquid insecticidal composition comprises:

Ammonium salt of coconut oil monoglyceride monosulphate One part byweight of this liquid dispersed in 50 to parts of water makes asatisfactory spray for most agricultural purposes.

Example II 1 part of DDT is dissolved in 4 parts of glycerylmonostearate at about 60 C. The mixture'is emulsified with about 5 partsof water containing 0.5% soap at about the same temperature. Afterthorough agitation the mixture is bottled. The suspension that forms oncooling is quite stable and disperses readily when mixed with additionalwater. One part of the suspension in 100 parts of water gives asatisfactory agricultural spray composition.

The advantages of applying the insecticide to a plant surface in aliquid polyhydric alcohol monoester are that the monoester serves tobind the insecticide to the fruit or other plant surface and to resistthe tendency of rain and weather to wash of! the insecticide whichremains dissolved in the ester. The insecticide, being in solution inthe monoester, is in a more effective form. A major advantage is thatwhen it is desired to remove the insecticide, as in the case of fruitafter it has been picked, this is readily accomplished by washing thefruit with an aqueous solution of soap or other emulsifying agent higherin concentration than that used in spraying, e. g., by agitating thefruit in the solution, spraying the fruit therewith, etc. The polyhydricalcohol monoester is very readily emulsified and removed under theseconditions, and the insecticide, being in solution in the ester, iseffectively removed at the same time.

Although the present invention has been described in connection withcertain illustrative embodiments of the invention, modification andvariations within the scope of the appended claims is contemplated.

We claim:

1. An insecticidal composition adapted for dispersion in water to form aspray for plants consisting essentially of an organic insecticide, anemulsifying agent and a liquid fatty acid monoester of a polyhydriccompound, said insecticide and emulsifying agent both being in solutionin said monoester.

2. An insecticidal composition adapted for dispersion in water to form aspray for plants consisting essentially of an organic insecticide and anemulsifying agent both dissolved in a fatty acid monoester of analiphatic polyhydric alcohol having from two to six carbon atoms permolecule.

8. An insecticidal composition as set forth in claim 2 in which a glycolmonoester is used.

4. An insecticidal composition adapted for dispersion in water to form aspray for plants consisting essentially ofdichlorodiphenyltrichloroethane and an emulsifying agent both dissolvedin propylene glycol monoesters of coconut oil fatty acids.

5. An insecticidal composition adapted for dispersion in water to form aspray for plants consisting essentially ofdichlorodiphenyltrichloroethane and an emulsifying agent both dissolvedin a liquid glycol monoester of fatty acids having from six totwenty-four carbon atoms per molecule.

6. An insecticidal emulsion concentrate adapted for dispersion in waterto form a spray for plants which comprises a fatty phase consistingessen- 6 tially of an organic insecticide dissolved in normally liquidpolyhydric alcohol monoester of higher fatty acids, an aqueous phase andan emulsifying agent, said emulsifying agent not exceeding about 2% byweight of said fatty phase and being soluble therein.

JOSEPH HENRY PERCY. HERBERT FRANK NEUMANN.

10 REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 2,233,447 Dolman Mar. 4, 19212,256,700 Armstrong Sept. 23, 1921 2,264,762 Knight Dec. 2, 19212,318,920 Brown May 11, 1943 2,349,814 Deonier et al May 30, 19442,423,457 Lynn July 8, 1947 2,432,607 Brown Dec. 16, 1947 2,442,760Dieter June 8, 1948 FOREIGN PATENTS Number Country Date 547,871 GreatBritain Sept. 15, 1942 OTHER REFERENCES War Dept. Tech, Bulletin #TBMed. 194-Aug.

17, 1945, page 31.

1. AN INSECTICIDAL COMPOSITION ADAPTED FOR DISPERSION IN WATER TO FORM ASPARY FOR PLANTS CONSISTING ESSENTIALLY OF AN ORGANIC INSECTICIDE, ANEMULSIFYING AGENT AND A LIQUID FATTY ACID MONESTER OF A POLYHYDRICECOMPOUND, SAID INSECTICIDE AND EMULSIFYING AGENT BOTH BEING IN SOLUTIONIN SAID MONOESTER.